You do not have to wait until a debt is due to determine whether it is worthless. A debt becomes worthless when there is no longer any chance the amount owed will be paid.

It is not necessary to go to court if you can show that a judgment from the court would be uncollectible. You must only show that you have taken reasonable steps to collect the debt. Bankruptcy of your debtor is generally good evidence of the worthlessness of at least a part of an unsecured and unpreferred debt.